Start by reading the instruction manual to your machine. Get a book like this: https://www.amazon.com/First-Time-Sewing-Step-Step/dp/1589238044. I recommend a book so you have something you can make notes in and refer back to when you need it. Then, practice on cheap, fairly light cotton (old sheets are perfect) until you can sew a reasonably straight line and can finish seam allowances. Make a pillowcase. Then get a pattern for a simple skirt and follow the directions. Sewing is all about geometry--fitting curves and pieces together, and a pattern will tell you how and in what order. When you pick a pattern, buy according to your measurements, NOT your ready-to-wear size.
Move on from there. You'll have many frustrating moments but keep at it and you'll be great soon enough. Don't try to skip ahead and go directly to self-drafting your own clothes or trying to work with difficult fabrics like satin until you have the interim steps. Until you now how fabric behaves and how to follow a pattern, you'll just be wasting your time and money.